System comprising a cellular network of capacitive pressure and shear-stress sensors and manufacturing process

Abstract

Disclosed is a system and to a process for manufacturing a system including a network of sensors including a sheet of dielectric material that is elastically deformable under compressive and shear stress, each cell of the network including a first capacitive sensor for sensing normal pressure in a first direction, a second capacitive sensor for sensing shear stress in a second direction and a third capacitive sensor for sensing shear stress in a third direction. Each capacitive sensor includes a first electrode fixed to the first side of the sheet of dielectric material and a second electrode fixed to the second side of the sheet of dielectric material, the first electrodes of the capacitive sensors of a given cell being connected in series to a first electrically conductive track connecting a row of cells of the network of sensors.

The invention claimed is: 
     
       1. A pressure sensor network system, comprising:
 a sheet of dielectric material elastically deformable in compression and shear, the sheet of dielectric material having a first face and a second face; 
 a network comprising a plurality of pressure sensor cells, the cells being arranged in at least three rows and at least three columns, each cell comprising a first capacitive sensor for sensing normal pressure in a first direction (Z), 
 each capacitive sensor having a first electrode fixed to the first face of the sheet of dielectric material and a second electrode fixed to the second face of the sheet of dielectric material, 
 said first electrode of the capacitive normal-pressure sensor of a cell being connected in series to a first electrically conductive track connecting a row of cells of the sensor network, and 
 the second electrode of the capacitive normal-pressure sensor of a cell being connected to a second electrically conductive track connecting a column of capacitive normal-pressure sensors of the sensor network; and 
 addressing means adapted to measure the electrical capacitance of a capacitive sensor located at the intersection of a row and a column, said row corresponding to a first track connected to said first electrode and said column corresponding to another track connected to one of said second electrodes, 
 wherein at least one cell of the sensor network includes a second capacitive sensor for sensing shear in a second direction (X) and a third capacitive sensor for sensing shear in a third direction (Y), 
 each capacitive shear sensor having a first electrode fixed to the first face of the sheet of dielectric material and a second electrode fixed to the second face of the sheet of dielectric material, said first and second electrodes of the capacitive shear sensors being comb-shaped, 
 said first electrodes of the capacitive sensors of a cell being connected in series, the second electrode of the capacitive sensor for sensing shear in the second direction (X) being connected to a third electrically conductive track connecting a row of capacitive sensors for sensing shear in the second direction (X) of the sensor network, and 
 the second electrode ( 6 ) of the capacitive sensor for sensing shear in the third direction (Y) being connected to a fourth electrically conductive track connecting a column of capacitive sensors for sensing shear in the third direction (Y) of the sensor network. 
 
     
     
       2. The pressure and shear sensor network system according to  claim 1 , wherein the sheet of dielectric material elastically deformable in compression and shear is a material selected from the group consisting of: a micro-architectured cork, an elastomer, a rubber, a urethane, a silicone, a butyl rubber, a polymer, a neoprene, a polyurethane, a polyisoprene, and an urethane foam. 
     
     
       3. The pressure and shear sensor network system according to  claim 2 , wherein said first electrically conductive track and the second electrically conductive track of a cell are connected to an electronic system adapted to measure a variation of the electrical capacitance of the capacitive normal-pressure sensor, the electronic system being adapted to deduce therefrom a normal pressure force applied to said capacitive normal-pressure sensor along the first direction (Z). 
     
     
       4. The pressure sensor network system according to  claim 2 , wherein at least one cell of the sensor network comprises a second capacitive sensor for sensing shear in a second direction (X) and a third capacitive sensor for sensing shear in a third direction (Y), each capacitive shear sensor being consisted of a first electrode fixed to the first face of the sheet of dielectric material and a second electrode fixed to the second face of the sheet of dielectric material, said first and second electrodes of the capacitive shear sensors being comb-shaped, said first electrodes of the capacitive sensors of a cell being connected in series, the second electrode of the capacitive sensor for sensing shear in the second direction (X) being connected to a third electrically conductive track connecting a row of capacitive sensors for sensing shear in the second direction (X) of the sensor network; and the second electrode ( 6 ) of the capacitive sensor for sensing shear in the third direction (Y) being connected to a fourth electrically conductive track connecting a column of capacitive sensors for sensing shear in the third direction (Y) of the sensor network. 
     
     
       5. The pressure and shear sensor network system according to  claim 1 , wherein said first electrode and said first electrically conductive track are printed on a sheet of electrically insulating and flexible material, and, respectively, wherein said second electrode and said other electrically conductive tracks are printed on another sheet of electrically insulating and flexible material. 
     
     
       6. The pressure sensor network system according to  claim 5 , wherein at least one cell of the sensor network comprises a second capacitive sensor for sensing shear in a second direction (X) and a third capacitive sensor for sensing shear in a third direction (Y), each capacitive shear sensor being consisted of a first electrode fixed to the first face of the sheet of dielectric material and a second electrode fixed to the second face of the sheet of dielectric material, said first and second electrodes of the capacitive shear sensors being comb-shaped, said first electrodes of the capacitive sensors of a cell being connected in series, the second electrode of the capacitive sensor for sensing shear in the second direction (X) being connected to a third electrically conductive track connecting a row of capacitive sensors for sensing shear in the second direction (X) of the sensor network; and the second electrode ( 6 ) of the capacitive sensor for sensing shear in the third direction (Y) being connected to a fourth electrically conductive track connecting a column of capacitive sensors for sensing shear in the third direction (Y) of the sensor network. 
     
     
       7. The pressure and shear sensor network system according to  claim 1 , wherein the first electrically conductive track and the second electrically conductive track of a cell are connected to an electronic system adapted to measure a variation of the electrical capacitance of the capacitive normal-pressure sensor, the electronic system being adapted to deduce therefrom a normal pressure force applied to said capacitive normal-pressure sensor along the first direction (Z). 
     
     
       8. The pressure sensor network system according to  claim 7 , wherein at least one cell of the sensor network comprises a second capacitive sensor for sensing shear in a second direction (X) and a third capacitive sensor for sensing shear in a third direction (Y), each capacitive shear sensor being consisted of a first electrode fixed to the first face of the sheet of dielectric material and a second electrode fixed to the second face of the sheet of dielectric material, said first and second electrodes of the capacitive shear sensors being comb-shaped, said first electrodes of the capacitive sensors of a cell being connected in series, the second electrode of the capacitive sensor for sensing shear in the second direction (X) being connected to a third electrically conductive track connecting a row of capacitive sensors for sensing shear in the second direction (X) of the sensor network; and the second electrode ( 6 ) of the capacitive sensor for sensing shear in the third direction (Y) being connected to a fourth electrically conductive track connecting a column of capacitive sensors for sensing shear in the third direction (Y) of the sensor network. 
     
     
       9. The pressure sensor network system according to  claim 1 , wherein the first electrically conductive track and the third electrically conductive track of a cell are connected to said electronic system, which is adapted to measure a variation of the electrical capacitance of the second capacitive sensor for sensing shear in the second direction (X), the electronic system being adapted to deduce therefrom the amplitude and direction of a shear force applied to said capacitive sensor for sensing shear along the second direction (X). 
     
     
       10. The pressure sensor network system according to  claim 1 , wherein the first electrically conductive track and the fourth electrically conductive track of a cell are connected to said electronic system, which is adapted to measure a variation of the electrical capacitance of the third capacitive sensor for sensing shear in the third direction (Y), the electronic system being adapted to deduce therefrom the amplitude and direction of a shear force applied to said third capacitive shear sensor along the third direction (Y). 
     
     
       11. The pressure sensor network system according to  claim 1 , wherein said electrically conductive tracks are connected to means for measuring a variation of electrical capacitance of the capacitive sensors by wired or wireless links. 
     
     
       12. The pressure sensor network system according to  claim 1 , further comprising:
 a device for displaying pressure and/or shear force measurements, 
 wherein the display device is configured to represent graphically, as a function of the arrangement of the sensor network, the normal pressure measured by each cell of the sensor network and/or simultaneously the amplitude and direction of the shear force measured by each cell of the sensor network. 
 
     
     
       13. A shoe sole comprising a pressure sensor network system according to  claim 1 .